cd tray button dead? means power failure. step one is remove that old bad shorted huge battery first. and run on AC pack only(even forever) bad power pack (or wrong kind) bad power jack on PC side it for sure needs service, guessing is not possible (or very expensive) if the P15-s420 (the dash matters ok./) Satellite P15-S420 (is the full name ok?) a true relic with only XP OS loaded. XP is trash, a pure virus magnet. 15 years old today. all batteries inside and outside are bad 15 years old not one will be good, and that is bad. the HDD will be bad too as will the CCFL LCD back lamps bad.(black screens forever) 2004 made, a pure relic with zero value.

worse yet is the DC jack is soldered down and all are cracked now. all are, if not parked on shelf for 15 years.
a better PC has pig tail jack that lasts 10x longer.
like HP 8540 has. and all top grade HP and Dell have.
not this toy grade old laptop

the big battery is optional remove it , it is bad.and run on AC for every (just not mobile)next this this stinking NiMh rechargeable battery,it only charges when PC is turned on so let PC run for 24hrs.to charge this, but in truth never seen one ever last 16years.not me nor do I expect that to happenbut its on the bottom of the motherboard, blue casingit must be unsolder, many are now leaking phosphates.its about dead center bottom mobo.

that program you run is just a toy to sell PCs.NO OS stated the first PC with this model markings was 2008 so is this XP running?if yes you using XP are doomed.seem new came with XP or VISTA and both are doomed now.zero support, XP is a hopeless virus magnet.MS VISTA has no recover modes but your service guide covers that. (google tohsihia support)The OEM new that and added ways to recover.1: the recovery built in to HDD, way.2: recovery disks (CD/DVD) lost. not sold now.3: or some 3rd parter APP that does all this , many types there are, only Toshiba manuals cover what .some were made in 2008so on cusp of VISTA. XP /Vista.what is it?vista has no MS repair modesso Toshiba put there own in the PC.that is covered in your toshiba U400 manualif your go there read that and read the chapter on RECOVERY for XP or VISTA as the case may be. and are diffrent, you answer is there.but those silly books assume the hdd is good.most are not this old. ok?main battery bad, and RTC coin cell bead.then bad HDD. (based on natural life of weak parts)

Are you using the installation disk that came with your printer?
If yes, then you uninstall everything you installed and download an updated version of the software from HP Support pages. and use that instead.
Please report back and rate help! Good Luck

old post answered late by terry
first off, is that code, what I means.
the poster forgot to say they were doing RECOVERY.
and that is what fails. (or bought the PC used just now and last owner put it in to recovery stuck there,.... no history stated.
it fails for 2 reasons, (or more)
1: someone replaced the hdd before, killing recovery dead.
a new HDD/SSD means OS gone and recovery partition too.
2: upgraded the OS with out using Toshiba media.

if the HDD is bad now, there will be no 0 key recovery possible
the maker does not sell recovery media on any old PC.
most OEM only do this for 1st 3 years
no OS stated by you at all.

now to fix a computer with not money
there is only 2 answers,
steal one, (lol)
or if HDD passes all HDD tests, load feel Linux.
I do not find anything free, every day for 70 years,
not yet,

brett gabs 1year old post.\
11 year old PC says maker,. full model number not stated.
I bet the PC is sold/ scrapped or fixed after 1 year?
but self shut down top cause are.:

1: the huge battery is shorted, take it out leave it out.
2: the power pack is dead, AC pack the PC must run on the AC pack or the (big battery out) may be dead, test it. ask.
3; overheated is it on a blanket? or bed, or desk are all vents cleaned and fan clean and funs runs fast while running too hot
we do simple heat tests (ask how,costs nothing) ask how to test
guessing will fail, if we guess 13 times. (or more if motherboard modules short)
came with VISTA, still VISTA?
there are more way's here are a bunch. .
lucky 13 ways
computers are complex for sure the windows, side.http://pcdied.com/shutsdown/shutsdown.html

the inverters fail 1%your question really is impossible. (how to get to)CCFL., NO photos of you showing panel rear and that STICKER.then you ask how to get the LCD out;. will good luck there see my last post on that topic

why even post until you open the back panel 100%remove the LCD paneland see what is there, most PC have 3 screen optonsand 3 makers of screens, so ONLY you opening itand see what screen actually is there, will work1: remove screen.2: see Toshiba sticker and P/N. and makers name and number too. (Samsung and LG are 2 top makers))3: then lock for the CCLF, the big clue is the Invereter cable goes to the CCFL array, 1 tube or 3 tubes on some.if you look at the screen and CCFL entry pointyou then (physical world is like this) we see3 possible ways in.1: easy it has a slide out tray?2: is a huge glue/plastic sandwich, impossible.3: has these silly metal bend tabs that snap off rendering my work useless, or I get invented with hot glue gun and rip it apart and find the tubes.spend $30 to $50 or tubes (sellers are scaplers)and make this work.

as you can see I have done this.what is inside your PC nobody knows, due to the facts stated above. (it's optional when new/built)

Remove the battery and see if it starts up fine, if not then try the following:

1. Unplug your charger cord.
2. Remove the battery.
3. Press and hold the "Power" button for 30 seconds or longer
4. Now plug back in the power/charger cord.
5. Now put the battery back in.
6. See if it starts up now, laptops often get stuck in hibernate mode.

13 year old PC,if you lost the BIOS admin password, that can be hard to reset but 13 year old PC are the most easyevery year it gets harder.did you google this first.the maker of the PC has no real form at all.so that is why you are here, because you can't ask the maker, but in all cases of all makers of PCs all there forums are not allowed to discuss this topic (hacking passwords)as of march 2018 this topic is illegall(sic)but we at fixya can tell you that you can google and read, or go to youtube, and see if someone has hack for this, did you?

the OEM page is this only

https://support.toshiba.com/support/navShell?cf=tais_kb

the hacking is here. I do not promote hacking but there is no other choices but and OEM fix or hacking or new MOBO.1 second search here shows. (youtube has many)https://www.youtube.com/watch?v=SxGviSv7EoA

then video is not very good, but shows locates at end clearly see the J1, jack it seen 2 squiggly line trances there of copper, jump the squiggly.